One of the greatest achievements to date in efforts to arrest the HIV epidemic was the dramatic success of the 076 clinical trial of antenatal and peripartum zidovudine (AZT) with brief AZT treatment of the child after, birth in reducing maternal-child HIV transmission (MCT). If used widely in clinical practice, this therapeutic intervention may greatly diminish the HIV epidemic among children, as most are infected by MCT. Yet our current NIDA-funded study of the influence of HIV-infected women's prenatal care and illicit drug use on the clinical outcomes of their children raises serious concerns about translating the 076 trial advance into clinical practice. Of 2,254 New York State (NYS) Medicaid-enrolled, HIV-infected women delivering singletons from 1985-90), 65% had too few prenatal visits according to an index adjusting for length of gestation. Untreated illicit drug user's had 60% higher odds of inadequate prenatal care than methadone-treated women. In this cohort, adequate prenatal care was associated with 50% lower odds of having a low birth weight infant. Our data also indicate that women using illicit drugs during pregnancy were more likely to have several characteristics such as advanced HIV- infection and smoking that we found to be associated with an increased risk of Ma. Unfortunately, drug users were under-represented in the 076 trials so the benefits and use of this potentially toxic therapy in this population remains an important question. In this continuation project, we propose to study prenatal care and birth outcomes for approximately 1700 NYS Medicaid-enrolled, HIV-infected parturient women in federal fiscal years (FFY) 1994-96 and to examine predictors of MCT for approximately 1100 of their infants delivered by mid-1996 and followed through FFY 1997. Data sources for this cohort include Medicaid claims-based research files and vital statistics records. As in our current project, we will conduct similar analyses in approximately 240 HIV-infected women and their children who are prospectively-followed at New York University (NYU), Bellevue Medical Center. Our research aims are: 1) To evaluate the impact of Medicaid initiatives to improve prenatal and HIV-related care on adequacy of prenatal care and birth outcomes among HIV-infected, drug-using women. 2) To assess the association of factors identified in aim #1 with receipt of antenatal AZT therapy. 3) To examine the effect of AZT on the risk of HIV infection among offspring of drug-using women. 4) To repeat aim #3 in the NYU/Bellevue cohort, supplementing these analyses with interview data regarding illicit drug use and maternal clinical and immune status factors not available for NYS Medicaid population. 5) To identify major birth defects among offspring of the NYS Medicaid cohort and to evaluate differences in rates of defects by maternal illicit drug use. This study unites the power of population-based research using Medicaid data with the specificity of analyses on a prospectively-followed cohort to extend our understanding of the use of attenuated AZT by women with a history of illicit drug use and the impact of AZT on transmission in actual clinical practice.